Objective To analyze the distribution characteristics of the single nucleotide polymorphism (SNP) site rs76206423 in the promoter region of the interleukin-2 receptor (IL-2R) β gene among Han males in a high radiation background area (HBRA) in Yangjiang City. Methods A total of 48 male participants from Tangkou Town, Yangxi County, Yangjiang City (HBRA group), and 51 male participants from Hengpo Town, Enping City (control group) were selected as the research subjects using the random number table method. Peripheral venous blood samples of participants from both groups were collected, and genomic DNA was extracted. The genotyping and allele frequency distribution of the rs76206423 (A/G) site in the IL-2R β promoter region was detected among the participants in both groups using the SNP detection method. The difference of allele frequencies between population in HBRA group and five area of East Asia, South Asia, Africa, Europe, and the Americas published in the Human Genome Project database from National Center for Biotechnology Information were analyzed. Results The allele frequencies of rs76206423 of population in both groups conformed to Hardy-Weinberg equilibrium (P>0.05). In the HBRA group, the AA genotype was predominant (64.6%), while the AG genotype was the most common in the control group (51.0%), with a significant difference (P<0.05). Population in both groups showed a predominance of the variant allele A (78.1% and 72.5%, respectively), with no significant difference (P>0.05). The frequency of the G allele of rs76206423 in the population in HBRA group was higher than those in South Asian, African, European, and American populations (all P<0.01), but showed no significant difference compared with East Asian populations (P>0.05). Conclusion In the Han male population from the HBRA in Yangjiang City, the rs76206423 site in the IL-2R β gene promoter region is predominantly composed of the wild-type A allele and AA genotype, indicating genetic stability and a relatively high degree of variation at this locus.

Objective To analyze the monitoring status of occupational hazard factors in key industry workplaces in a city of the Pearl River Delta area from 2019 to 2023. Methods A total of 1 548 enterprises in 12 key industries of the city were selected as the research subjects using the judgmental sampling method. Their monitoring data for dust, chemical factors, and noise, along with the occupational health management status of the enterprises were analyzed. Results Among the 1 548 enterprises, large and medium-sized enterprises accounted for 2.7% and 13.4%, while small and micro enterprises accounted for 83.9%. A total of 474 enterprises exceeded the national limit in the detection of occupational hazard factors, with an exceedance rate of 30.6%. The rates of workers exposed to occupational hazard factors, dust, chemical factors, and noise were 29.4%, 6.9%, 21.0%, and 13.0%, respectively, all showing a downward trend year by year (all P<0.05). The training rates for occupational health among enterprise managers, responsible persons, and workers were 84.1%, 84.2%, and 91.2%, respectively. The detection rates for abnormal occupational health examinations among workers exposed to dust, chemical factors, and noise were 0.2%, 0.3%, and 0.5%, respectively. The setting rates of warning signs and warning instructions among enterprises for dust, chemical toxins, and noise were 87.3%, 91.1%, and 89.5%, respectively. The setting rates for dust, toxic chemical, and noise control facilities were 72.4%, 75.4%, and 46.0%, with effectiveness rates of 70.5%, 56.6%, and 55.2%, respectively. The distribution rates of personal protective dust masks, gas masks, and noise earplugs/earmuffs were 91.9%, 83.8%, and 86.4%, with wearing rates of 80.8%, 70.5%, and 76.4%, respectively. The detection rates of exceeding national limits for dust, chemical factors, and noise in the work site of occupational hazard factors were15.2%, 1.0%, and 21.6%, respectively. The detection rates of exceeding national limits for dust, chemical factors, and noise in the workplace of occupational hazard factors were 2.4%, 2.5%, and 12.3%, respectively. The exceedance rate for noise in work site showed an upward trend year by year (P<0.01). Conclusion Occupational disease prevention and control work in the key industries of this city needs strengthening. It is essential to further enhance the regular monitoring and preventive measures of occupational hazard factors in enterprises, improve protective measures, strengthen the use of personal protective equipment, and enhance occupational health training and supervision, to effectively reduce the risk of occupational diseases and protect workers' occupational health rights.

Noise is a common occupational hazard in workplaces. Long-term exposure to high-intensity noise mainly causes occupational noise-induced hearing loss (ONIHL). The development of ONIHL is irreversible, and there is currently no cure. At present, risk assessment methods based on noise exposure intensities mainly include risk index assessment method, Engineering Professional Council assessment method in United Kingdom (EDC assessment method in UK), National Institute of Occupational Safety and Health assessment method in United State (NIOSH assessment method in US), and International Standardization Organization assessment method (ISO assessment method). However, the risk index assessment method is subjective and does not consider the effectiveness of workers wearing protective equipment. The EDC assessment method in UK defines ONIHL differently from China. The NIOSH assessment method in US and ISO assessment methods have population data sources that deviate from China, which can lead to bias in risk assessment. In the future, it is necessary to further carry out application research on the risk assessment of ONIHL in Chinese noise-exposed workers, compare the applicabilities of various assessment methods, conduct large-sample population epidemiological studies for verification, and fully utilize the risk-prediction function to prevent and control ONIHL.

ObjectiveTo analyze the results of fit testing and its influencing factors on half-mask respirator among workers exposed to organic solvents. Methods A total of 84 workers exposed to organic solvents were selected as the research subjects using a convenience sampling method. The qualitative fit test apparatus of respiratory protection was tested after the workers had put on the half-mask respirats, and 11 facial indicators of the subjects were measured. Results The overall pass rate of the respirator fit testing was 71.4% (60/84). The lowest pass rate was 63.1% (53/84), which occurred during bending movements of workers. The head width, minimum forehead width, face length, nose length, nose depth, head circumference and head length were higher in workers who passed respirator fit testing, compared with those in the failing group (all P<0.05). The result of binary logistic regression analysis showed that gender and face width were influencing factors of the respirator fit testing (both P<0.05). Female workers had a lower pass rate of the fit testing than male workers, and workers with larger face width had a lower pass rate in the fit testing. Conclusion Drastic movement may lead to a decrease in the seal of half-mask respirator of workers exposed to organic solvents. When providing half-mask respirator to workers exposed to organic solvents, employers need to pay attention to the fit of respirators of female works and those with larger face width to ensure the effectiveness of respiratory protection for workers.

ObjectiveTo explore the protective effect of hearing protectors worn by noise-exposed workers and its influencing factors. Methods A total of 329 occupational noise-exposed workers were selected as the research subjects by judgment sampling method. A questionnaire survey on the use of ear protectors and individual suitability tests was conducted. Intervention was carried out for those whose personal attenuation rating (PAR) did not pass the baseline standard. Results The median (M) and the 25th and 75th percentiles of baseline PAR were 17.0 (5.0, 22.5) dB. The baseline PAR of the workers who were male, aged 25-<35 years, with a working experience of 5-<15 years, with a college degree or above, wearing ear protectors for 5-<15 years, knowing the right way to wear ear protectors, and workers who wore ear protectors correctly during work was relatively high (all P<0.01). The unqualified rate of baseline PAR of the study subjects was 32.8%. The unqualified rate of baseline PAR of workers in automobile manufacturing enterprises was lower than that of workers in plastic enterprises and textile enterprises (9.2% vs 43.6%, and 9.2% vs 50.0%, both P<0.01). The M of the 108 unqualified worker on baseline PAR was improved after intervention (22.0 vs 1.0 dB, P<0.01). The rates of knowing the right way to wear ear protectors, wearing ear protectors correctly during work, and receiving training on wearing ear protectors correctly for the research subjects were 88.1%, 84.8%, and 86.6%, respectively. Workers in automobile manufacturing enterprises and plastic enterprises had higher rates of knowing the right way to wear ear protectors, wearing ear protectors correctly during work, and receiving training on wearing ear protectors correctly than those in textile enterprises (all P<0.01). Conclusion Gender, age, working experience, education level, duration of wearing ear protectors, knowledge and use of ear protectors correctly are influencing factors of the protective effect of ear protectors for noise-exposed workers.

Objective:To investigate the occupational noise hazards in five machinery manufacturing enterprises, and to evaluate the individual noise reduction values and influencing factors of workers wearing hearing protection device (HPD) by individual fit testing.Methods:From November 2021 to January 2022, 5 machinery manufacturing enterprises in Bao'an District of Shenzhen were selected to conduct an occupational health survey to understand the noise exposure level of workers. The 3MTM E-A-RfitTM fitness test system was used to test the baseline individual sound attenuation value level (PAR) of the daily wear of the ear protecters for 485 workers in typical noise working positions. Workers whose PAR values could not meet the requirements of noise reduction at work were instructed to wear and repeated tests were conducted. PAR results of the workers before and after the intervention were collected and analyzed.Results:The noise workers who received the suitability test were mainly distributed in 24 types of work, the job noise exposure level was 80.2 dB (A) ~ 95.0 dB (A), and the job noise excess rate was 52.5% (138/263). The median baseline PAR [ M ( Q1, Q3) ] for 485 workers was 6.0 (0.0, 14.0) dB. The baseline PAR of male workers, those with more than 15 years of working experience, those with more than 15 years of using ear guards, those who considered ear guards comfortable to wear, those with college degree or above, and those exposed to noise level 90 dB (A) were higher, and the difference was statistically significant ( P<0.05). A total of 275 workers (56.7%) did not pass the baseline PAR test, and there was no statistically significant difference in the intervention rate of workers in different noise groups ( P>0.05). PAR in subjects who did not pass baseline after intervention increased from 0.0 (0.0, 3.0) dB to 15.0 (12.0, 18.2) dB. Conclusion:The workplace noise hazard of machinery manufacturing enterprises is serious, and there is a great difference between the baseline PAR and the nominal value of the hearing guard worn by the noise exposed workers. The intervention measures can effectively improve the protective effect of wearing ear protectors.

Objective:To assess the efficacy of silicone earplugs in protecting workers exposed to noise in a typical manufacturing environment, and to provide training interventions for workers who do not achieve the anticipated noise reduction levels, as well as examining the spectral characteristics of earplug attenuation.Methods:From June to August 2022, a total of 294 noise-exposed workers in two manufacturing enterprises equipped with the same type of earplug were studied by cluster sampling method, by conducting questionnaire surveys, collecting data, fitting tests, and providing trainings, the current noise exposure levels of workers in the industry as well as the perception about the earplug were understood. Additionally, the attenuation before and after intervention in workplace were measured, the spectral characteristics of noise reduction were were described and compared.Results:The percentage of workers with Personal Attenuation Rating (PAR) of 0 is 32.7% (96/294), and the baseline pass rates are all below 60%. There were no significant differences in pass rates based on gender, age, noise exposure, education level, or cognition of earplug effectiveness. After adjusting the way that earplugs are worn or changing the type of earplugs, all workers were able to meet their noise reduction requirements. The median PAR improvement for both companies is above 10 dB. The noise attenuation of the earplug vary with frequency, with lower attenuation at 4 000 Hz and higher attenuation at 8 000 Hz, showing some deviation from the nominal values.Conclusion:The difference between the actual sound attenuation value of earplugs and the nominal value is related to the noise frequency. When using silicone earplugs, attention should be paid to the spectral composition of the noise in the workplace.

Objective:To investigate the occupational noise hazards in five machinery manufacturing enterprises, and to evaluate the individual noise reduction values and influencing factors of workers wearing hearing protection device (HPD) by individual fit testing.Methods:From November 2021 to January 2022, 5 machinery manufacturing enterprises in Bao'an District of Shenzhen were selected to conduct an occupational health survey to understand the noise exposure level of workers. The 3MTM E-A-RfitTM fitness test system was used to test the baseline individual sound attenuation value level (PAR) of the daily wear of the ear protecters for 485 workers in typical noise working positions. Workers whose PAR values could not meet the requirements of noise reduction at work were instructed to wear and repeated tests were conducted. PAR results of the workers before and after the intervention were collected and analyzed.Results:The noise workers who received the suitability test were mainly distributed in 24 types of work, the job noise exposure level was 80.2 dB (A) ~ 95.0 dB (A), and the job noise excess rate was 52.5% (138/263). The median baseline PAR [ M ( Q1, Q3) ] for 485 workers was 6.0 (0.0, 14.0) dB. The baseline PAR of male workers, those with more than 15 years of working experience, those with more than 15 years of using ear guards, those who considered ear guards comfortable to wear, those with college degree or above, and those exposed to noise level 90 dB (A) were higher, and the difference was statistically significant ( P<0.05). A total of 275 workers (56.7%) did not pass the baseline PAR test, and there was no statistically significant difference in the intervention rate of workers in different noise groups ( P>0.05). PAR in subjects who did not pass baseline after intervention increased from 0.0 (0.0, 3.0) dB to 15.0 (12.0, 18.2) dB. Conclusion:The workplace noise hazard of machinery manufacturing enterprises is serious, and there is a great difference between the baseline PAR and the nominal value of the hearing guard worn by the noise exposed workers. The intervention measures can effectively improve the protective effect of wearing ear protectors.

Objective:To assess the efficacy of silicone earplugs in protecting workers exposed to noise in a typical manufacturing environment, and to provide training interventions for workers who do not achieve the anticipated noise reduction levels, as well as examining the spectral characteristics of earplug attenuation.Methods:From June to August 2022, a total of 294 noise-exposed workers in two manufacturing enterprises equipped with the same type of earplug were studied by cluster sampling method, by conducting questionnaire surveys, collecting data, fitting tests, and providing trainings, the current noise exposure levels of workers in the industry as well as the perception about the earplug were understood. Additionally, the attenuation before and after intervention in workplace were measured, the spectral characteristics of noise reduction were were described and compared.Results:The percentage of workers with Personal Attenuation Rating (PAR) of 0 is 32.7% (96/294), and the baseline pass rates are all below 60%. There were no significant differences in pass rates based on gender, age, noise exposure, education level, or cognition of earplug effectiveness. After adjusting the way that earplugs are worn or changing the type of earplugs, all workers were able to meet their noise reduction requirements. The median PAR improvement for both companies is above 10 dB. The noise attenuation of the earplug vary with frequency, with lower attenuation at 4 000 Hz and higher attenuation at 8 000 Hz, showing some deviation from the nominal values.Conclusion:The difference between the actual sound attenuation value of earplugs and the nominal value is related to the noise frequency. When using silicone earplugs, attention should be paid to the spectral composition of the noise in the workplace.

Background Most of the studies on grading and classification of occupational health compre-hensive risks for specific employers still remain in the establishment and description of methodology, and practical application studies are rarely reported. Objective To explore the application of an occupational disease hazards comprehensive risk assessment method issued by the National Disease Control and Prevention Bureau in conjunction with the National Health Commission and a self-developed occupational health grading and classification method in petroleum refining enterprises, and to provide practical experience for the implementation of differentiated law enforcement by relevant regulatory authorities. Methods Two occupational health grading and classification methods were practiced in three petroleum refining enterprises in Guangdong Province. The occupational hazards comprehensive risk assessment method was provided by the Notice on Carrying out Pilot Work of Occupational Health Classification Supervision and Law Enforcement of the National Disease Control and Prevention Bureau and the National Health Commission. The principle was to derive the occupational health risk level according to nature of occupational hazards, exposure level, and number of workers exposed to them in an employer, and then to classify them into Class A, Class B, and Class C by combining with local occupational health management status level. The occupational health grading and classification method was self-developed according to available domestic and foreign occupational health risk assessment methods. Its principle was to calculate the risk level of each workstation in an employer based on published carcinogenicity classification or LD₅₀/LC₅₀ of chemical toxicants, level of noise, exposure parameters such as exposure level and exposure frequency, estimate the comprehensive risk R_o of the target employer by the Romanian comprehensive risk calculation method, and then calculate a comprehensive risk R_o' weighted by the occupational health management index of the target employer and classify it into class A, class B, and class C. Finally, assessment results, scope of application, inquired indicators, advantages,disadvantages and professional competence requirements of the two grading and classification methods were compared. Results The occupational hazards that were evaluated in three enterprises in this study were benzene, toluene, xylene, gasoline, hydrogen sulfide, and noise. The exposure levels of benzene, toluene, xylene, and gasoline were all below 10% OEL (occupational exposure limit), and hydrogen sulfide and noise were disqualified. Occupational hazards such as benzene and hydrogen sulfide were serious occupational hazards in the three enterprises, and the number of workers exposed was 461, 912, and 224, respectively; the HRs (hazard ratings) of benzene, toluene, xylene, gasoline, hydrogen sulfide, and noise were level 5, 3, 2, 3, 5, and 3 respectively. The occupational health management status of the three enterprises was graded as B, A, and B, respectively by the occupational disease hazards comprehensive risk assessment method. The occupational health management index of the three enterprises was graded as B, A, and A, respectively by the occupational health grading and classification method. The comprehensive risk assessment results showed that two enterprises classified into as the highest class C and one into class B by the occupational disease hazards comprehensive risk assessment method, while all three enterprises were classified into class B by the occupational health grading and classification method. Conclusion The two grading and classification methods are not consistent in the evaluation results of petroleum refining enterprises, and there are differences in the evaluation scope, indicators to be collected, and professionalism. It is recommended that occupational health regulators should fully consider the advantages and disadvantages of the two methods and choose the appropriate assessment method according to the actual regulatory purpose.